问题

Simon, how old is your grandpa this year—______. And we are planning a special birthday party for his ______ birthday this Sunday.
A:Ninetieth; ninety
B:Ninety; ninety
C:Ninety; ninetieth
D:Ninetieth; ninetieth;
B:Ninety; ninety
C:Ninety; ninetieth
D:Ninetieth; ninetieth;
正确答案是: